Amazon's stock price has soared over the last year, raising the massive online shopping giant's market value by 57 percent. The trend continued Tuesday as shares closed at $1,252.70, and the company's market capitalization was above $600 billion.

GBH Insights researchers also believe the e-retailer captured a greater portion of 2017 holiday sales over the prior year.

"Over the last month our research at GBH has indicated Amazon has dominated e-commerce sales, with our estimates indicating the company captured between 45% to 50% of all holiday online retail sales vs. 38% during this holiday sales period in 2016," Daniel Ives, technical research analyst at GBH, told CBS News in a statement.

Gates is listed as the second-richest person at a not-too-shabby net worth of $93.3 billion. Warren Buffett comes in third at $87.2 billion. And No. 4 is Facebook founder Mark Zuckerberg at $77.5 billion.

Last year, Amazon also acquired Whole Foods grocery store chain and partnered with Nike. And it's rumored that Amazon will soon break into the health care market.

In 2013, Bezos bought the Washington Post for $250 million.

According to CBS, Amazon's sales account for about one-third of all e-commerce transactions.